实验2

任务1

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 5
int main() {
  int number;
  int i;
  srand(time(0));   // 以当前系统时间作为随机种子
  for(i = 0; i < N; ++i) {
    number = rand() % 100 + 1;
    printf("20490042%04d\n", number);
 }
  return 0;
}

问题1：按当前时间随机抽了5个学号

问题2：生成1到100之间的随机整数并赋值给number

问题3：让学号的长度一样

问题4：让每次生成的学号不一样

 

任务2

#include <stdio.h>
int main() {
  int choice, quantity;
  float total_price = 0, amount_paid, change;
  while (1) {
    printf("\n自动饮料售卖机菜单:\n");
    printf("1. 可乐 - 3 元/瓶\n");
    printf("2. 雪碧 - 3 元/瓶\n");
    printf("3. 橙汁 - 5 元/瓶\n");
    printf("4. 矿泉水 - 2 元/瓶\n");
    printf("0. 退出购买流程\n");
    printf("请输入饮料编号: ");
    scanf("%d", &choice);
    if (choice == 0)
      break;
          if (choice < 1 || choice > 4) {
      printf("无效的饮料编号，请重新输入。\n");
      continue;
   }
    printf("请输入购买的数量: ");
    scanf("%d", &quantity);
    if (quantity < 0) {
        printf("购买数量不能为负数，请重新输入。\n");
    continue;
   }
    if(choice == 1 || choice == 2)
      total_price += 3 * quantity;
    else if(choice == 3)
      total_price += 5 * quantity;
    else
      total_price += 2 * quantity;
    printf("请投入金额: ");
    scanf("%f", &amount_paid);
    change = amount_paid - total_price;
    printf("本次购买总价: %.2f 元\n", total_price);
    printf("找零: %.2f 元\n", change);
    total_price = 0;
 }
  printf("感谢您的购买，欢迎下次光临！\n");
  return 0;
}

问题1：如果运行两次以上的话，金额会叠加起来

问题2：结束剩余的代码，重新循环

 

任务3

#include<stdio.h>

int main(){
    char color;
    while (scanf("%c",&color)==1){
        getchar();
        switch(color){
            case 'r':printf("stop!\n");break;
            case 'g':printf("go go go \n");break;
            case 'y':printf("wait a minute\n");break;
            default:printf("something must be wrong...\n");break;
        }
    }
    return 0;
}

 

任务4

#include<stdio.h>

int main(){
    double cost;
    double total=0.0;
    double max_cost=0.0;
    double min_cost=20000.0;
    printf("输入今日开销，直到输入-1终止：\n");
    while(1){
        scanf("%lf",&cost);
        if(cost == -1){
            break;
        }
        total += cost;
        if(cost > max_cost){
            max_cost = cost;
        }
        if(cost < min_cost){
            min_cost = cost;
        }
    }
    printf("今日累计消费总额：%.1f\n",total);
    printf("今日最高一笔开销：%.1f\n",max_cost);
    printf("今日最低一笔开销：%.1f\n",min_cost);
    return 0;
}

 

任务5

 

#include<stdio.h>

int main(){
    int a,b,c;
    while(scanf("%d%d%d",&a,&b,&c)==3){
        if(a+b<=c||a+c<=b||b+c<=a||a<=0||b<=0||c<=0){
            printf("不能构成三角形\n");
            continue;
        }
        int max,mid,min;
        if(a>=b&&a>=c){
            max = a;
            mid = b>=c?b:c;
            min = b<=c?b:c;
        }
        else if(b>=a&&b>=c){
            max = b;
            mid = a>=c?a:c;
            min = a<=c?a:c;
        }
        else{
            max = c;
            mid = a>=b?a:b;
            min = a<=b?a:b;
        }
        if(a==b&&b==c){
            printf("等边三角形\n");
        }
        else if(a==b||a==c||b==c){
            printf("等腰三角形\n");
        }
        else if(min*min+mid*mid==max*max){
            printf("直角三角形\n");
        }
        else{
            printf("普通三角形\n");
        }
    }
    return 0;
}

 

任务6

 

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int main(){
    srand((unsigned int)time(NULL));
    int lucky_day = rand() % 30 + 1;
    printf("猜猜2026年4月哪一天是你的luckyday\n");
    int guess;
    int i;
    for (i = 0;i < 3;i++){
        if (i == 0){
            printf("开始喽，你有3次机会，猜吧（1-30）：");
        }
        else{
            printf("再猜（1-30):");
        }
        scanf("%d",&guess);
        if(guess == lucky_day){
            printf("哇，猜中了：）\n");
            return 0;
        }
        else if(guess > lucky_day){
            printf("你猜的日期晚了，你的luckyday在前面哦\n");
        }
        else{
            printf("你猜的日期早了，你的luckyday还没到呢\n");
        }
    }
    printf("次数用光啦。4月你的luckyday是%d号\n",lucky_day);
    return 0;
}